sr20 Posted July 10, 2023 Report Share Posted July 10, 2023 Had the ECU for a couple of years, everything has been fine but very recently started seeing the engine management light coming on whilst driving which relates to these codes Sporadically I see the IAT temp high error and then some days later the oil temp high error, nothing has changed on the ECU, some days of driving though we see no errors at all We clear the code during the drive and it never comes back on that drive, car running perfectly, then on the next drive we may get one or the other code which we clear and again doesn't come back on that drive When we look at current temps after the event, everything looks fine and within error high values Anything to be concerned about? Thanks in advance PS can attach recent logs but have never managed to catch the error during a logging session Quote Link to comment Share on other sites More sharing options...
Confused Posted July 10, 2023 Report Share Posted July 10, 2023 It could be a Error High or Error Low value set incorrectly on the Analogue Input, which could be that it's actually reaching a high temp (but high enough that it's triggering the fault), or it could be an intermittent wiring issue and an actual problem. But yeah, a copy of the tune plus logs showing this will definitely aid troubleshooting. Quote Link to comment Share on other sites More sharing options...
sr20 Posted July 19, 2023 Author Report Share Posted July 19, 2023 Many thanks for your prompt response and apologies for not replying sooner, I've been trying to capture the errors as they are happening in a live log but haven't been able to reproduce them so attached is a log captured after I started seeing the errors (albeit the errors didn't actually occur during this logging session) Also attached are some screenshots of the IAT temp and oil temp ECU settings showing the high and low values (captured today - engine wasn't running) Quote Link to comment Share on other sites More sharing options...
DerekAE86 Posted July 19, 2023 Report Share Posted July 19, 2023 Attach your tune file too Quote Link to comment Share on other sites More sharing options...
sr20 Posted July 19, 2023 Author Report Share Posted July 19, 2023 1 hour ago, DerekAE86 said: Attach your tune file too Done! thanks for reminding me! savedtune.pclx Quote Link to comment Share on other sites More sharing options...
DerekAE86 Posted July 20, 2023 Report Share Posted July 20, 2023 The calibration for these sensors are actually 5v = cold, 0v = hot. So when it's giving you a "high" error things are actually very cold because the voltage is above the "high error" point. Was it colder than usual on the days the check light came on? To avoid this happening in the future just change the error high voltages to 5v. That way the ECU would have to see a value higher than actually possible unless there was something very wrong (like the 5v line shorted to 12v, or the ECU's internal regulator failing) Quote Link to comment Share on other sites More sharing options...
sr20 Posted July 21, 2023 Author Report Share Posted July 21, 2023 On 7/20/2023 at 7:19 AM, DerekAE86 said: The calibration for these sensors are actually 5v = cold, 0v = hot. So when it's giving you a "high" error things are actually very cold because the voltage is above the "high error" point. Was it colder than usual on the days the check light came on? To avoid this happening in the future just change the error high voltages to 5v. That way the ECU would have to see a value higher than actually possible unless there was something very wrong (like the 5v line shorted to 12v, or the ECU's internal regulator failing) Thanks for the response, actually just the opposite, the first time we saw this it was an unusually hot month here in the UK, I think it was 33C on the day we got it, and all other times its been a very hot ambient temperature too, that said we have driven it on even hotter days and never got the errors. I guess my concern is If the configuration is wrong that doesn't really explain why we have only just started getting the errors after 2 years of perfect operation Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 22, 2023 Report Share Posted July 22, 2023 A high error on two temp sensors occurring at the same time would suggest a bad ground. Either a loose ground connection to the sensors somewhere or something like a bad engine ground so starter current is passing through ECU ground when cranking etc. Set up ECU logging to run all the time, recording the raw voltages on the temp pins as well as the bat voltage, temps, fault codes etc, then you will have a log saved in memory that you can download next time it happens. Quote Link to comment Share on other sites More sharing options...
sr20 Posted July 23, 2023 Author Report Share Posted July 23, 2023 On 7/22/2023 at 1:22 AM, Adamw said: A high error on two temp sensors occurring at the same time would suggest a bad ground. Either a loose ground connection to the sensors somewhere or something like a bad engine ground so starter current is passing through ECU ground when cranking etc. Set up ECU logging to run all the time, recording the raw voltages on the temp pins as well as the bat voltage, temps, fault codes etc, then you will have a log saved in memory that you can download next time it happens. Ok I finally managed to capture the error, it happened twice today, once on the outbound journey, once on the return so seems to be becoming more prevalent, ambient temperature outside about 21C, log uploaded, let me know if you need anything else! Thanks! PC Datalog - 2023-07-23 12;12;15 pm.zip Quote Link to comment Share on other sites More sharing options...
DerekAE86 Posted July 23, 2023 Report Share Posted July 23, 2023 The oil temp signal is shooting up to 4.96v briefly after it's been heatsoaked at around 75+deg for awhile. Either the sensor is dying or you've got an intermittent short to 5v on the signal wire of the sensor. Quote Link to comment Share on other sites More sharing options...
sr20 Posted July 23, 2023 Author Report Share Posted July 23, 2023 1 hour ago, DerekAE86 said: The oil temp signal is shooting up to 4.96v briefly after it's been heatsoaked at around 75+deg for awhile. Either the sensor is dying or you've got an intermittent short to 5v on the signal wire of the sensor. Thanks sir, yes I see it, screenshot attached, and at 4.96v the oil temp reads zero, so as you mentioned in an earlier thread I think in addition to diagnosis I need to reverse the error high/low values too Quote Link to comment Share on other sites More sharing options...
Confused Posted July 23, 2023 Report Share Posted July 23, 2023 You can't "reverse the error high/low", these are high and low voltage that will send the input into an error state. As has been said, this indicates either a sensor failure, or a wiring issue. Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 23, 2023 Report Share Posted July 23, 2023 I would set up a new blank page in PC Link with a big digital gauge displaying AN Temp 3 raw voltage, sit the laptop somewhere you can see it then go around the loom and bend/wiggle/yank/stretch anything to do with the oil temp wiring - including where there may be ground splices and especially around the sensor connector and terminals etc. That will usually find if there is a bad connection anywhere. If that doesnt find anything then I would probably look at swapping the sensor next. Confused and DerekAE86 2 Quote Link to comment Share on other sites More sharing options...
sr20 Posted July 23, 2023 Author Report Share Posted July 23, 2023 ah right @confused got you! Sounds like a plan @adamw, will give that a go and post back Thanks both! Quote Link to comment Share on other sites More sharing options...
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